- #1
RedBarchetta
- 50
- 1
Homework Statement
A tank is full of water. Find the work W required to pump the water out of the spout. Use the fact that water weighs 62.5 lb/ft3.
a = 5
b = 9
c = 12
The Attempt at a Solution
So for this one, you have to set up a formula for a rectangular box of water.
The biggest rectangle is 5(or y) by 9, in relation to a smaller rectangle that is w by 9. I can also setup a relationship between the two to find that y/w=9/9 or y=w. So therefore we can produce an equation for the area of one rectangle.
dA=9y
Now the thickness of this rectangle is extremely small so the thickness is dy.
dV=9y dy
The density of water is 62.5 lb/ft^3, so this one rectangular-box of water is:
dM=562.5y dy
To find the force, we multiply by the force of gravity, I used 32.2 ft/sec^2.
dF=18112.5y dy
So our work is dF times the distance. This is where I become lost. Would the distance be vertical or horizontal? would it be (5-y) or (12-y)?
Sorry to bother you guys again! Thanks for all of the help so far!